There's things that one can, or cannot, do. No living person can do absolutely everything that comes to mind.
My strong sides are troubleshooting and debugging/error fixing and problem-solving gigs.
I do, although very rarely, a "blank sheet" or "full scale" development. Most often I do wordpress plugins, cs-cart,zen-cart,x-cart, sometimes even Joomla modules and core php standalone scripts.
Things like visual layout/styling/design are NOT 'my stuff' and, although I do occasionally work such jobs, I am not very good at.
And I NEVER do Mobile Apps development.